The first chapter is a brief review of the geology,
geography and the soils in Iceland, with particular
reference to peat soils.
The field work (Chapter 2) included measuring the
thickness of organic layers between dated tephra layers
and it was found that the mean rate of thickening of the
peat was slowest 0.1 mm/year in the period 4500 to 2900 B. P.,
but fastest 0.26 mm/year in the period since 1104 A. D.
Two profiles were selected for detailed study, one in
north Iceland, and the other in west Iceland.
Micromorphology, physical, and chemical properties
were investigated, see-Chapters 3,4 and 5 respectively;
and a review of peat soil classification and the application
to the soils studied is given in Chapter 6.
The main constituents observed in the thin sections
were underground plant organs, fine organic material, and
mineral material. Woody, cork, epidermal and lign ifi ed
tissues were best preserved, parenchymatous tissue had
predominantly disappeared, but was present in some leaf
and herbaceous root residues. Conspicuous secondary
mineral phenomena included bog iron, pyrite and siderite;
and in Chapter 7a hypothesis is proposed for the formation
of s ider it e.
The range of hydraulic conductivies was from about
9.10-3 to 1_ 10-4 cm sec-1 .
The moisture content at
saturation was mainly > 90 , and 10 to 20; 4 at pr 4.2.
Bulk density was mainly 0.1 to 0.2 g cm-1 in organic layers
and up to 0.5 g cm-1 in those rich in mineral material.
Most samples shrunk to less than half the original volume
upon oven drying and it was concluded that it is important
to consider shrinkage when moisture retention is determined.
The pH in water was highest at 6.8 in the top layer
of the profile in north Iceland, but was mainly 4.4 to
5.0 in the organic layers. The loss on ignition of the
organic layers varied mainly from 40; ') to 90 The C/N
range was normally 17 to 30, but lowest at 15 in the top
layer of the profile from North Iceland